Analysis of 6000 skin biopsies of the national leprosy control program in Mexico

Six thousand skin biopsy specimens taken from April 1978 to January 2002 under conditions as specified by the National Leprosy Control Program (NLCP), were analyzed to obtain information about the work of the program and contribute to the knowledge of this illness in the Mexico. Six-thousand request forms for histologic exam of the NLCP were reviewed. Sixty-two percent of the requests had all the required information and in 38% one or more data items were omitted. The age range was 2 to 98 yrs with a median of 50 yrs; a small number of cases was observed in the age group of 0 to 14 yrs, and the peak was in the age group of 41 to 50 yrs. Of the 6000 biopsies, 3693 were classified. Polar lepromatous (LL) was the most common form of the disease, in 60.3% of cases. Twice as many cases were multibacillary leprosy (MB) as paucibacillary (PB). MB predominated in males, and PB predominated in females. The Cohen's kappa index (kappa) of clinical-histological agreement was 0.202 (95% CI 0.184-0.219) and showed a poor grade of agreement between clinical and histologic diagnosis, with a level of significance of 0.05 (p <0.001). The results may indicate the end of leprosy in Mexico, a country in which the national goal of elimination was reached in 1994, with a prevalence since the year 2000 of 0.17/10 000.